Stack layout

Hello
i want to design simple wizard in swt(not jface) with 2 pages in the first page i have next button that lead me to the second page. and in the second page i have previous page that lead me to the first page.
i succeed to make the next page :
display = new Display();
shell = new Shell(display,SWT.SHELL_TRIM ^ SWT.MAX ^ SWT.RESIZE);
nextButton = new Button(shell, SWT.PUSH | SWT.CENTER);
nextButton.setText("Next");
nextButton.setBounds(475, 334, 107, 30);
nextButton.addSelectionListener(new SelectionAdapter()
{
public void widgetSelected(SelectionEvent evt)
{
stackLayout = new StackLayout();
shell.setLayout(stackLayout);
shell.layout();
//add gui elements to the second page.
//add previous button in the second page
backbutton = new Button(shell, SWT.PUSH | SWT.CENTER);
backbutton.setText("back");
backbutton.setBounds(75, 302, 107, 30);
backbutton.addSelectionListener(new SelectionAdapter()
{
public void widgetSelected(SelectionEvent evt)
{
//to do????????????
}
});
});

i don;t know how to add event handling to the back button,the next button above is working fine ,but i don;t know how to return to the first page can any one please help me ?